Wheaton News

Mapping Ganymede

The largest moon in the solar system, Ganymede could qualify as a planet, if it weren’t for the fact that it orbits Jupiter. So, creating a map of Ganymede is a massive undertaking, given the satellite’s size, its distance from Earth and the apparent complexity of its geologic history.

It was big news when the map was completed, particularly since researchers from NASA and the European Space Agency (ESA) are currently planning an unmanned mission to Jupiter and its moons for 2020.

The new map, drawn from evidence collected by the Voyager and Galileo spacecraft, supports a theory developed by Wheaton Associate Professor of Geology Geoffrey Collins, Wes Patterson of the Johns Hopkins University Applied Physics Laboratory (APL) about the “grooved” surface features of Ganymede.

“When you look at really close-up pictures of these grooves, a lot of them look like huge normal faults, a geological feature produced by pulling the surface apart, like the Hudson River Valley or the Basin and Range [Province] in Nevada,” Collins says. “We really want to know what forces pulled the surface apart.”

The theory advanced by Collins and Patterson is that the forces that created these grooves involve orbital resonances of two of Jupiter’s three other satellites—Europa and Io. (For every revolution of Jupiter made by Ganymede, Europa orbits the planet twice and Io circles it four times, according to Scientific American.)

Graphic separation of the tectonic features on Ganymede, from oldest (blue) to youngest (red). The brown areas are ancient dark terrain that has not been torn apart by tectonic activity. (Image courtesy of Geoffrey Collins.)

Wheaton students have been an integral part of this work, as Collins has regularly included undergraduates in aspects of the research from classification of grooved terrain on the moon’s surface to creating an image database of crater and impact basins on the satellite.

Students who have worked on the project include Karrie-Sue Farrar ’03, Jonathan McBee ’04, Emily Martin ’06, and Jonathan Kay ’08. Kay also was a coauthor on the Ganymede map paper, which was submitted over the summer.

Collins’ research explores geological processes on the icy satellites of the outer solar system. He has been involved with various NASA projects such as the Galileo mission to Jupiter and the Cassini mission to Saturn. A 2007 study by Collins and a research partner suggested that there is a sea of liquid water trapped beneath the ice on Enceladus, raising questions about whether the Saturn moon might feature other conditions favorable to life.